This invention relates to a new system for sampling the gas contained in an environment such as the containment building surrounding a sodium-cooled nuclear power reactor, or the stack of an industrial plant. The gas to be sampled may be an elemental species, or may be a mixture of many elements or gaseous compounds. The purpose of obtaining a sample of the gas may be to ascertain the qualitative and quantitative content of the gas for purposes of documentation or control.
In certain environments, the gas to be sampled either contains, or potentially may contain, mixtures, suspensions or aerosols. These terms refer to conditions in which the gas contains solid particles or liquid droplets considered tramp material herein, either dissolved, suspended, or merely mixed in the gas.
The solid matter may range greatly in size. Encompassed in the term "tramp material" herein are particles of solid matter as large as ashes commonly contained in stack gas, or as small as smoke or dust particles. The tramp material contained in the gas may interfere with the sampling process in a variety of ways. The sample lines may become plugged, or require frequent servicing. The tramp material may be radioactive, posing an obstacle to radiation measurements of the gas.
The exclusion of solid tramp material from the sample might be accomplished by filters. This is not, however, suitable for some ranges of tramp material size and concentration. Very small particles may pass through a filter of a given mesh while a very large concentration of tramp material could rapidly clog or saturate a filter.
A particular sampling problem could arise following a coolant leak in the piping of a sodium-cooled reactor. The sodium concentration in the containment building gas, in the form of an aerosol, could then be very high, precisely when the sampling need may be most important.
It is desired to provide a sampler which can sample a gas containing tramp material without degraded performance.